Determination of Trace Amount of Cupric Ion in Water with Flow Injection-ion Selective Electrode

Ion selective electrode with flow injection technique was applied to the determination of trace amount of Cu(Ⅱ) in circulating cooling water and cyclic activated sludge system (CASS) effluent water.Various influential factors,including the length of the mixing coil,flow rate of the carrier,sampling volume,total ion strength adjusting buffer solution were studied and optimized.The detection limit (3s/k) of the method was 2.2 μg·L-1.Precision of the method was tested at the concentration levels of 20 and 40 μg·L-1 of Cu(Ⅱ) ion for 11 determinations,values of RSD′s found was 1.94% and 1.66%,respectively.The proposed method was used in the analysis of samples from circulating cooling water and CASS effluent water,giving values of recovery in the range of 95.6%-104.0%.